LOCATION ERD SDEstablished Series
TAXONOMIC CLASS: Fine, smectitic, calcareous, mesic Vertic Endoaquolls
TYPICAL PEDON: Erd clay - on a plane, southeast-facing slope of less than 1 percent in native grass. When described the soil was moist to 24 inches. (Colors are for moist soil unless otherwise stated.)
A--0 to 3 inches; very dark gray (10YR 3/1) clay, dark gray (10YR 4/1) dry; weak medium subangular blocky structure parting to moderate fine granular; very hard, very firm, very sticky, very plastic; slightly alkaline; clear smooth boundary. (2 to 6 inches thick)
Bg1--3 to 10 inches; very dark gray (5Y 3/1) clay, gray (5Y 5/1) dry; moderate coarse blocky structure parting to moderate medium and fine blocky; extremely hard, extremely firm, very sticky, very plastic; slight effervescence; moderately alkaline; gradual smooth boundary.
Bg2--10 to 20 inches; very dark gray (5Y 3/1) clay, gray (5Y 5/1) dry; weak very coarse blocky structure parting to strong medium and fine blocky; extremely hard, extremely firm, very sticky, very plastic; slight effervescence; slightly alkaline; diffuse smooth boundary. (Combined Bg horizons 10 to 22 inches thick)
Bzg--20 to 28 inches; dark gray (5Y 4/1) clay, gray (5Y 5/1) dry; weak coarse blocky structure; extremely hard, extremely firm, very sticky, very plastic; common medium accumulations of salts; slight effervescence; slightly alkaline; diffuse smooth boundary. (6 to 12 inches thick)
Czg--28 to 37 inches; olive gray (5Y 4/2) clay, olive gray (5Y 5/2) dry; massive; extremely hard, extremely firm, very sticky, very plastic; common medium accumulations of salts; strong effervescence; slightly alkaline; diffuse smooth boundary.
Cg--37 to 60 inches; grayish brown (2.5Y 5/2) clay, light brownish gray (2.5Y 6/2) dry; few fine faint gray (N 5/)) and brown (10YR 5/3) mottles; massive; extremely hard, extremely firm, very sticky, very plastic; strong effervescence; slightly alkaline.
TYPE LOCATION: Tripp County, South Dakota; about 2 miles west and 4 miles north of Winner; 100 feet south and 75 feet west of the northeast corner of sec. 35, T. 100 N., R. 77 W.
RANGE IN CHARACTERISTICS: Solum thickness typically is 20 to 34 inches, but ranges from 18 to 40 inches. Most pedons are leached of carbonates to depths of about 3 inches, but some contain free carbonates at the surface. The thickness of the mollic epipedon ranges from 14 to 26 inches and commonly extends into or through the Bg horizon. The soil is slightly alkaline or moderately alkaline throughout. When the soil is dry, cracks 1/2 to 2 inches wide and several feet long extend downward through the solum. Exchangeable sodium in the Bzg and Cg horizons ranges from 8 to 20 percent. Electrical conductivity ranges from 8 to 16 mmhos per centimeter in the Bzg and Cg horizons.
The A horizon has hue of 10YR or 2.5Y, value of 2 or 3 and 4 or 5 dry, and chroma of 1 or 2. It typically is clay, but is silty clay in some pedons.
The Bg horizon has hue of 5Y or 2.5Y, value of 2 or 3 and 4 or 5 dry, and chroma of 1 or 2. It is clay or silty clay averaging between 45 and 60 percent clay.
The Bzg horizon has hue of 5Y or 2.5Y, value of 4 or 5, and 5 or 6 dry, and chroma of 2 or less. If value is 5 and chroma is 2, there are mottles with high chroma present. Accumulations of salts range from few to many.
The Cg horizon has hue of 5Y or 2.5Y, value of 4 or 5 and 5 to 7 dry, and chroma of 1 or 2. Accumulations of salts range from few to many.
COMPETING SERIES: This is the Solomon series. Solomon soils have thicker A horizons and formed under warmer temperatures and higher rainfall.
GEOGRAPHIC SETTING: Erd soils are on nearly level flood plains and terraces. Slope gradients range from 0 to 1 percent. These soils formed in clayey sediments. Mean annual temperature ranges from 46 to 50 degrees F, and mean annual precipitation from 18 to 23 inches.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Carter, Hurley, Koll, Millboro, Promise and Witten soils. The well drained or moderately well drained Carter and Hurley soils and the well drained Millboro and Promise soils are on slightly higher landscapes. Kolls soils are in closed depressions. They area very-fine. Witten soils are in swales. Witten soils are better drained and have argillic horizons.
DRAINAGE AND PERMEABILITY: Somewhat poorly drained. Surface runoff is medium or high. Permeability is very slow. A seasonal water table is at depths of 2 to 5 feet in the spring of some years.
USE AND VEGETATION: About equally divided between cropland and native grassland. Crops are mostly small grain and alfalfa. Native vegetation dominant is mainly western wheatgrass, green needlegrass, and blue grama.
DISTRIBUTION AND EXTENT: South-central South Dakota. It is inextensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Denver, Colorado
SERIES ESTABLISHED: Tripp County, South Dakota, 1975.
REMARKS: Diagnostic horizons and features recognized in this pedon are: mollic epipedon - the zone from the surface of the soil to a depth of 20 inches (A, Bg1, Bg2 horizons).